title: Diversity and biofilm-production ability among isolates of Escherichia coli phylogroup D belonging to ST69, ST393 and ST405 clonal groups.
abstract: BACKGROUND
  Phylogenetic group D Escherichia coli clones (ST69, ST393, ST405) are increasingly reported as multidrug resistant strains causing extra-intestinal infections. We aim to characterize inter- and intraclonal diversity of a broad sample (isolates from different geographic locations and origins with variable antibiotic resistance profiles, 1980-2010) and their ability to adhere and form biofilm by both a modified quantitative biofilm producing assay and Field Emission Scanning Electron Microscopy (FESEM).
  
  
  RESULTS
  High virulence scores were observed among ST69 (median 14/range 9-15) and ST393 (median 14/range 8-15) clones, particularly enriched in pap alleles, iha, kpsMTII-K5 and ompT, in contrast with ST405 (median 6/range 2-14) isolates, exhibiting frequently fyuA, malX and traT. All ST69 and ST393 and only two ST405 isolates were classified as ExPEC. Biofilm production was detected in two non-clinical ST69 and three ST393 isolates from different origins showing variable virulence profiles. Within each clonal group, and despite the high diversity of PFGE-types observed, isolates from different countries and recovered over large periods of time were clustered in a few groups sharing common virulence gene profiles among ST69 (n = 10 isolates) and ST393 (n = 9 isolates) (fimH-iha-iutA-kpsMTII-K5-(traT)-sat-(ompT)-papA-papEF-papGII-papC) or ST405 (n = 6 isolates) (fimH-traT-fyuA-malX).
  
  
  CONCLUSIONS
  This study highlights the circulation of highly transmissible ST69, ST393 and ST405 variants among different settings. Biofilm production seems not to be directly correlated with their epidemiological success.
authors.affiliation: Departamento de Microbiologia, REQUIMTE, Faculdade Farmácia Universidade Porto, Rua Jorge Viterbo Ferreira n° 228, 4050-313 Porto, Porto, Portugal. angelasilvanovais@gmail.com
authors.forename: Ângela
authors.initials: Â
authors.lastname: Novais
authors.forename: Claudia
authors.initials: C
authors.lastname: Vuotto
authors.forename: João
authors.initials: J
authors.lastname: Pires
authors.forename: Carolina
authors.initials: C
authors.lastname: Montenegro
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Donelli
authors.forename: Teresa M
authors.initials: TM
authors.lastname: Coque
authors.forename: Luísa
authors.initials: L
authors.lastname: Peixe
mesh_terms: D018441:Biofilms / Q000254:growth & development*; D016000:Cluster Analysis; D016521:Electrophoresis, Gel, Pulsed-Field; D004926:Escherichia coli / Q000145:classification* / Q000235:genetics / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000235:genetics; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D008855:Microscopy, Electron, Scanning; D058889:Molecular Typing; D037521:Virulence Factors / Q000235:genetics
chemical_list: D029968:Escherichia coli Proteins; D037521:Virulence Factors